自动生成Java实体类

整体代码:

package funny.jdbc;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
public class GenEntityTool {
private String tablename = "books_info";
private String[] colnames; // 列名数组
private String[] colTypes; // 列名类型数组
private int[] colSizes; // 列名大小数组
private boolean f_util=false; //是否需要导入包java.util.*

private boolean f_sql=false; //是否需要导入包java.sql.*

public GenEntityTool() {
  Connection conn = DBSession.getConnection(); // 得到数据库连接
  String strsql = "select * from " + tablename;
  try {
   PreparedStatement pstmt = conn.prepareStatement(strsql);
   ResultSetMetaData rsmd = pstmt.getMetaData();
   int size = rsmd.getColumnCount(); // 共有多少列
   colnames = new String[size];
   colTypes = new String[size];
   colSizes = new int[size];
   for (int i = 0; i < rsmd.getColumnCount(); i++) {
    colnames = rsmd.getColumnName(i + 1);
    colTypes = rsmd.getColumnTypeName(i + 1);
    if(colTypes.equalsIgnoreCase("datetime"))
    {
     f_util=true;
    }
    if(colTypes.equalsIgnoreCase("image") ||colTypes.equalsIgnoreCase("text"))
    {
     f_sql=true;
    }
    colSizes = rsmd.getColumnDisplaySize(i + 1);
   }
   String content=parse(colnames, colTypes, colSizes);
   try {
    FileWriter fw=new FileWriter(initcap(tablename)+".java");
    PrintWriter pw=new PrintWriter(fw);
    pw.println(content);
    pw.flush();
    pw.close();
   } catch (IOException e) {
    e.printStackTrace();
   }
  } catch (SQLException e) {
   e.printStackTrace();
  } finally {
   DBSession.closeConnection(conn);
  }
}
/**
  * 解析处理(生成实体类主体代码)
  */
private String parse(String[] colNames, String[] colTypes, int[] colSizes) {
  StringBuffer sb = new StringBuffer();
  if(f_util)
  {
   sb.append("import java.util.Date;\r\n");
  }
  if(f_sql)
  {
   sb.append("import java.sql.*;\r\n\r\n\r\n");
  }
  sb.append("public class "+initcap(tablename)+" {\r\n");
  processAllAttrs(sb);
  processAllMethod(sb);
  sb.append("}\r\n");
  System.out.println(sb.toString());
  return sb.toString();
  
}
/**
  * 生成所有的方法
  * @param sb
  */
private void processAllMethod(StringBuffer sb)
{
  for(int i=0;i<colnames.length;i++)
  {
   sb.append("\tpublic void set"+initcap(colnames)+"("+sqlType2JavaType(colTypes)+" "+colnames+"){\r\n");
   sb.append("\t\tthis."+colnames+"="+colnames+";\r\n");
   sb.append("\t}\r\n");
  
   sb.append("\tpublic "+sqlType2JavaType(colTypes)+" get"+initcap(colnames)+"(){\r\n");
   sb.append("\t\treturn "+colnames+";\r\n");
   sb.append("\t}\r\n");
  }
}
/**
  * 解析输出属性
  * @return
  */
private void processAllAttrs(StringBuffer sb)
{
  for(int i=0;i<colnames.length;i++)
  {
   sb.append("\tprivate "+sqlType2JavaType(colTypes)+" "+colnames+";\r\n");
  
  }
}
/**
  * 把输入字符串的首字母改成大写
  * @param str
  * @return
  */
private String initcap(String str)
{
  char[] ch = str.toCharArray();
  if (ch[0] >= 'a' && ch[0] <= 'z') {
   ch[0] = (char) (ch[0] - 32);
  }
  return new String(ch);
}
private String sqlType2JavaType(String sqlType)
{
  if(sqlType.equalsIgnoreCase("bit"))
  {
   return "bool";
  }
  else if(sqlType.equalsIgnoreCase("tinyint"))
  {
   return "byte";
  }
  else if (sqlType.equalsIgnoreCase("smallint"))
  {
   return "short";
  }
  else if(sqlType.equalsIgnoreCase("int"))
  {
   return  "int";
  }
  else if(sqlType.equalsIgnoreCase("bigint"))
  {
   return "long";
  }
  else if(sqlType.equalsIgnoreCase("float"))
  {
   return "float";
  }
  else if(sqlType.equalsIgnoreCase("decimal") ||sqlType.equalsIgnoreCase("numeric")||sqlType.equalsIgnoreCase("real"))
  {
   return "double";
  }
  else if(sqlType.equalsIgnoreCase("money")||sqlType.equalsIgnoreCase("smallmoney"))
  {
   return "double";
  }
  else if(sqlType.equalsIgnoreCase("varchar") ||sqlType.equalsIgnoreCase("char")||sqlType.equalsIgnoreCase("nvarchar")||sqlType.equalsIgnoreCase("nchar"))
  {
   return "String";
  }
  else if(sqlType.equalsIgnoreCase("datetime"))
  {
   return "Date";
  }
  
  else if(sqlType.equalsIgnoreCase("image"))
  {
   return "Blob";
  }
  else if(sqlType.equalsIgnoreCase("text"))
  {
   return "Clob";
  }
  return null;
}
public static void main(String[] args) {
  new GenEntityTool();
}
}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/mxz55/archive/2008/10/29/3174678.aspx